Everyone has seen magenta, that delightfully pink purple hue, but did you know it’s hiding a juicy scientific secret? Magenta is what is known as a non-spectral or extra-spectral color. Unlike most colors for example red and blue that can produced with a prism and are made up of one wavelength of light; magenta requires two wavelengths. As you can see below when you overlap two rainbows magenta appears!

[W]hat does the brain do when our eyes detect wavelengths from both ends of the light spectrum at once (i.e. red and violet light)? Generally speaking, it has two options for interpreting the input data:

a) Sum the input responses to produce a colour halfway between red and violet in the spectrum (which would in this case produce green – not a very representative colour of a red and violet mix) b) Invent a new colour halfway between red and violet Magenta is the evidence that the brain takes option b – it has apparently constructed a colour to bridge the gap between red and violet, because such a colour does not exist in the light spectrum. Magenta has no wavelength attributed to it, unlike all the other spectrum colours.

If you look at a standard CIE chromaticity diagram, which maps wavelengths of light according to human perception, you’ll note that every point along the curve corresponds to a single wavelength of light. Magenta, as it were, lies along what’s commonly called the “pink-purple line” that runs across the bottom. All colors along this line do not exist as single wavelengths. But, all points inside the “color bag” above that line do not exist as single wavelengths, either.

Magenta’s special status may even have medical applications. On the Color Matters site the New Frontiers of Science section mentions “Color scientist, John J. Stapleton, Pte., … is unweaving the rainbow and presenting new theories about the “how and why” of color and color vision. Furthermore, he has applied these theories to machines that may save lives: a medical x-ray machine to detect breast cancer.”

With such interesting physics hiding just under the surface of everyday colors the new frontiers of color science are indeed luminous.

Colour Studio works on projects approaching color in a scientific manner. Check out this infographic we put together to demonstrate our belief that “the right color choice always has a reason behind it.”